HUNTINGTON, Utah  Rescue workers aimed a third borehole Tuesday toward a spot at the back of the Crandall Canyon mine where they think six trapped coal miners may have fled when a collapse nine days ago left them with no escape route.

At the same time, mine co-owner Robert Murray said mechanized efforts to clear the main tunnel entrance of debris and rubble were gaining momentum and that crews might be able to reach the miners' possible location in five to seven days.

"It continues to go slow. It is very difficult," said Richard Stickler, head of the Mine Safety and Health Administration.

Searchers were looking for signs of life in the mine, which tunnels deep inside a mountain in the Manti-La Sal National Forest in eastern Utah.

Cameras lowered into two previous holes drilled from the mountain surface revealed images of open spaces amid the debris and tools that the miners likely were using when some of the mine's walls collapsed in the pre-dawn hours of Aug. 6.

Crews used bulldozers to cut a road along the rocky backside of the mountain that allowed them to move a drilling rig and begin drilling the third hole, nearly 9 inches wide. Murray said the third hole could reach its target by late today.

That hole is aimed at a small ventilated area in the back of the mine where air is evacuated from the tunnel. Murray said miners may have moved there in search of good air and would have been trained to go to such a location to await rescue.

"This is where the miners are, we think they are, below there," Murray said, pointing to the drilling location. Workers had drilled nearly half the 1,414-foot length, he said, and were putting in place equipment to slant the drill bit to its precise target.

If the third hole fails to produce signs of the men, Murray said engineers had already calculated where to position a fourth search hole toward the center of the mine, continuing what he has called a trial-and-error drilling search.

If those are not successful, he said, "At that point, we're running out of possibilities."

Meanwhile, rescue miners were boring through rubble in the mine's main entrance tunnel. Murray said workers had cleared 700 of the 2,000 feet of tunnel. Getting to the end will take days, he said.

The miners are moving slowly to ensure they do not cause another collapse and trap themselves, Murray said. There have been instances where miners survived 14 days before being rescued.

To report corrections and clarifications, contact Reader Editor Brent Jones. For publication consideration in the newspaper, send comments to letters@usatoday.com. Include name, phone number, city and state for verification.

Unidentified miners clear the mine passageway of the Crandall Canyon Mine in an effort to reach six trapped miners inside the mine.

Conversation guidelines: USA TODAY welcomes your thoughts, stories and information related to this article.
Please stay on topic and be respectful of others. Keep the conversation appropriate for interested readers across the map.